基于虚拟参考反馈整定的激光定向能量沉积过程控制OA

During laser-directed energy deposition(L-DED),the melt pool characteristics are highly correlated with heat accumulation,which can easily lead to dimensional deviations in the manufactured components.To address the problem that existing PID controllers mostly rely on preset parameters and trial-and-error methods to determine the optimal control parameters—resulting in time-consuming procedures and low intelligence—a virtual reference feedback tuning(VRFT)-PID adaptive control method is proposed.An image processing algorithm for the melt pool(median filtering,grayscale conversion,binarization,morphological processing,and ellipse fitting)is used to extract the melt pool width.Using the melt pool width as feedback,a VRFT-PID adaptive controller is designed to adjust the laser voltage in real time,automatically updating the PID parameters at preset time intervals of 10 seconds,thereby achieving stable control of the melt pool width during the L-DED process.An integrated melt pool monitoring and control system is established to experimentally validate the VRFT-PID adaptive control method.The experimental results show that the dimensional accuracy of the components fabricated using the VRFT-PID adaptive control method is improved,and this improvement in accuracy exhibits a good correlation with the consistency of the melt pool width.